Welcome to the
NAG Fortran Library, Mark 21
1 Introduction
Welcome! This booklet provides an introductory overview to the latest mark (edition) of the NAG Fortran Library. This versatile
Fortran-based product is for use by computer users who
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program in the Fortran programming language, or |
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program in other programming languages that can call Fortran-based software, or |
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use one of the large number of application packages (such as Microsoft® Excel) that can call Fortran-based software – see more about the versatility of this product in Section 2.2.
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The booklet contains useful information about the Library for readers who are new to NAG products and for existing users of
this product who are updating to Mark 21.
Please note that all the documents referred to in this booklet are provided on the release medium and can also be found on
the NAG
web site under NAG Fortran Library documentation.
If you are new to NAG, please go to Section
2.
If you are already a NAG ‘regular’, then please read on.
If you have used, installed or supported the NAG Fortran Library at previous marks, here is where to find out more about what
has changed at this mark.
The document entitled ‘
Mark 21 News – NAG Fortran Library’ lists the library routines that have been added at Mark 21. The total number of new routines added is 284, bringing the
total number of user-callable routines to 1532 of which 1469 are documented. New areas of functionality include large scale
eigensolvers, direct solvers for sparse linear systems, mixed effects regression and copula distributions.
‘
Mark 21 News – NAG Fortran Library’ also lists routines that have been withdrawn at this mark, and routines scheduled for withdrawal at a later mark.
The
Installer's Note is, as at previous marks, the document to read, if you are responsible for installing the Library at your site. Even though
you may be familiar with the Library and installation procedures, we encourage you to read this latest version. You will
find details of particular changes made at this mark (e.g., in the computer environment used to assemble and test the Library)
that may be significant for you and your users, as compared to previous marks.
Likewise, users of the Library are encouraged to read the
Users' Note supplied with this mark.
If you are an occasional, rather than a regular, user of the NAG Library, it may be useful to refer, as a reminder, to Section
2 of the Essential Introduction, which gives important advice on issues such as correct parameter calling, error handling and
thread safety.
Section
3 of this booklet lets you know about other NAG products and services, and if you wish to discuss any of them further with
us, we would be delighted to hear from you.
Finally, we remind NAG ‘regulars’ to check out the NAG
web site often. NAG policy is to make increasing use of the NAG
web site to enhance the flow, relevance and quality of information and support to its users, both regulars and newcomers. There is
also a reminder of how to contact NAG in Section
4.
2 Guide for Newcomers
2.1 About NAG
Founded in 1970 as an inter-university collaborative software project in the United Kingdom, NAG became an incorporated not-for-profit
organisation in 1976. Today NAG employs over 60 people in the UK, USA and Japan and has an extensive international network
of distributors. NAG has retained its not-for-profit status and its dedication to providing first-class products and technical
support.
From its beginning to the present day, NAG has produced high-quality software components that are robust, reliable and portable
across a wide range of platforms and operating systems, from the smallest PC to the most modern supercomputers. As Barbara
Raw, in Program Now, The Advanced Programmers' Journal said:
- ‘You can't criticize the NAG Library – as far as numerical algorithms are concerned it IS the standard.’
NAG has also been involved in many collaborative ventures with universities and research bodies around the world, contributing
and receiving expertise through such involvement, and thus ensuring that it remains at the forefront in research and development.
NAG is widely recognised for its long and distinguished contribution to the scientific and technical computing community through
its participation, largely at its own expense, in a number of activities to promote standards, develop an underlying corpus
of numerical software, and to promulgate best practice. These activities have included taking part in the development of high-quality
public domain software packages, most notably LAPACK and the BLAS, and in the specification of successive standards of the
Fortran programming language.
If you want to read more about the history, aims and organisation of NAG, please visit the NAG
web site.
2.2 About this Product
When compared with other commercially available numerical libraries the NAG Library is indisputably the largest tailored collection
of numerical and statistical software components. It is also widely regarded by experts in the field as the best documented,
best supported, most intensively tested and most actively developed of any such products. As well as its size and consistency,
its quality is a clear differentiator, particularly when compared to some public domain software.
Because of NAG's commitment to enhancement, both in terms of functionality and in the software engineering techniques at the
heart of its development process, users of the NAG Library can look forward to the prospect of an expanding set of functionality,
that is fully supported and meticulously documented, and available for calling from a growing number of computing languages,
packages and environments.
As well as Fortran and C of course, the
environments in which NAG Library components can be embedded include Delphi, Visual Basic, VBA, Excel,
Fortran 95,
Java, C# and C++. Performance-enhanced versions for multi-processor systems are also available via the NAG SMP Library.
To keep up-to-date with these exciting developments, be sure to check the NAG
web site regularly for the latest news. Another way of keeping up-to-date with product development and new releases of software at
NAG is to subscribe to our e-newsletter, NAGNews. If you would like to receive the newsletter simply email the Response Centre
or visit our
web site to register online.
2.3 Range of Contents
At Mark 21, the NAG Fortran Library contains 1532 user-callable routines. These are organised in the form of chapters, of
which there are 44. To see the breadth and depth of coverage now provided by the NAG Fortran Library, please refer to the
Library Contents.
2.4 World Class Documentation
Underpinning the quality of all NAG software is its renowned and comprehensive documentation. The software in the Library
is accompanied by thorough documentation, giving you the detailed information you need to help you carry out your work quickly
and efficiently. Documentation available for the NAG Fortran Library includes:
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Installer's Note. Used by those responsible for installing the Library at your site. Particular changes at this Mark, as compared to previous
Marks, will be included in this document.
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Users' Note. Essential reading for every user of the Library, the Users' Note provides implementation-specific detail that augments the information provided in the product documentation.
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Essential Introduction. Essential reading for every prospective user of the Library, this document provides information fundamental to the successful
use of the Library. It begins with a description of the product and documentation, describes key issues regarding product
use, and gives details of NAG's support facilities.
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The NAG Fortran Library Manual. Includes all the documentation listed above along with detailed information on the structure
of the library, a listing and details on use of the routines and documentation, and other helpful information such as example
programs. The manual has been provided, in full, on the release medium and can also be found on the NAG web site under Fortran Library documentation. In both cases, HTML index files provide easy navigation to all the PDF format documents.
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Example Programs. A major and arguably unique innovation made by NAG from its very beginning was to insist upon a fully worked
example program for each user-callable routine in its Library. The example program provides a relatively straightforward
application of its associated Library routine to provide answers to a meaningful problem. With the exception of utility routines,
the policy of providing such examples has been maintained throughout the history of the Library because it was and is seen
as a major element in the support of library users.
The Mark 21 Library documentation contains 1244 fully worked examples, and these are all available in machine-readable form,
on the release medium and on the NAG web site.
We know from many contacts with users of the NAG Library, just how useful these examples have proven to be, and we encourage
newcomers particularly to look at a selection of examples.
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2.5 Case Studies
An important and growing form of reference is the set of user application studies now available via the NAG
web site. The current case studies describe actual use of NAG software in a wide variety of fields such as:
- Utilities: optimizing the performance of a major electricity-generating plant
- Transportation: averting potential major traffic disruption
- Enterprise Resource Management: adding analytics for sharper performance
- Environment Protection: using NAG's numerics and its class-leading visualization system, IRIS Explorer, to build environmental
applications
- Manufacturing – Design: using IRIS Explorer to design hi-tech footwear
- Manufacturing – Electronics: eliminating debugging cycles in semiconductors
- Manufacturing – Steel: streamlining production through NAG-based analysis
When you have successfully developed your application using NAG Library software and wish to contribute it to the set of published
case studies, we will be delighted to hear from you!
2.6 What You Need to Know
If your role is to install the NAG Fortran Library at a site, then the key document for you is the
Installer's Note on the release medium. That note provides a number of important pieces of information, including:
- the computing environment in which the particular system version (the ‘implementation’, to use a NAG term) was compiled and
tested;
- the computing environment(s) in which the supplied implementation is considered suitable for use;
- details of the software licensing mechanism;
- description of the installation process itself;
- further information about options in the way that you can make the Library available to your users – these might refer to
vendor-supplied sub-libraries of optimized linear algebra software, for example.
If you are a new user of the NAG Library, or are about to take on the role of user support, the two key documents on the release
medium for you are:
- The Users' Note, which describes any specific characteristics of using the NAG Library on your particular platform – it is very important
to ensure that you are using the right implementation of the Library for your computing platform.
- The Essential Introduction to the NAG Fortran Library Manual is, as the title suggests, essential reading for any prospective user of the Library.
Its sections contain advice and information on:
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the organisation of the Library and conventions used; |
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the use of the Library; |
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how to find your way through to the very extensive set of library documentation; |
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how to obtain support from NAG; |
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the background to NAG; |
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references for the interested reader. |
2.7 Support from NAG
NAG's enduring aim is to ensure that all its customers gain maximum benefit from the investment they make when they license
NAG products and services. The first method of achieving this is by the continuing development of products and services, which
are well designed for their purpose and engineered to high quality standards, with all the painstaking preparation and testing
that those standards require.
When you have licensed software from NAG, our aim is to ensure that you:
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receive it in a timely manner, |
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can install it simply and satisfactorily, |
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can readily exploit its functionality for your applications. |
The NAG
web site provides a valuable resource for product information, frequently-asked questions, implementation availability, technical
documentation and demonstrations as well as general information about NAG.
From time to time, you may need to contact us if you need further information or advice. The NAG Response Centres provide
central points of contact for any query about NAG products and services. Enquiries are of a wide variety and include questions
concerning:
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product functionality; |
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product availability for specific computer systems; |
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product usage for a particular user application; |
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product installation; |
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order progress; |
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documentation availability; |
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possible software errors. |
The Response Centres can be contacted by telephone, fax, e-mail or conventional mail. See the NAG
web site for details.
If your enquiry is of a technical nature that requires specialist skills to answer, then it will be referred, by the Response
Centre, to the relevant technical specialist. The support provided through this facility is one of the most praised aspects
of the customer services provided by NAG. The collective experience of the colleagues who provide this service is very extensive.
Below we mention some key advice based on that experience.
2.8 Tips from the NAG Response Centre
NAG draws upon the experience gained through user feedback generally, and through the NAG Response Centre in particular, and
applies that experience in developing successive versions of NAG products to make them easier to use and more robust. For
the NAG Fortran Library, here are the ‘top tips’.
- Regarding installation, the largest number of queries received relate to software licensing issues. NAG is committed to developing
and refining the licensing mechanisms in use so that as far as possible they are:
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easy to install and maintain; |
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unobtrusive in relation to legitimate use; |
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effective in preventing illegitimate use and piracy. |
NAG firmly believes that its pursuit of that policy is not only in its best interest, but also in the best interests of its
user base, both site installation managers and users. We therefore ask that installers pay particular note to the information
given in the relevant section of the Installer's Note. If you see ways in which the information given there can be improved, please let us know. We will be pleased to hear from
you.
- In terms of routine usage queries from users, undoubtedly the largest single group of problems relate to
calling
parameter issues.
For example:
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has the NAG Library routine been called with the correct number of parameters? |
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do all the parameters have the correct type? |
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are array parameters set properly? |
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is the error-detection flag (IFAIL) being used OK? |
Section 2.2 of the Essential Introduction addresses these issues, and Section 2.3 of the Essential Introduction deals with
‘Error Handling and the Parameter IFAIL’, which is another very important facet of the NAG Library that newcomers to the Library
should note.
3 The NAG Range of Products and Services
Both newcomers to the NAG Fortran Library and current users may be unfamiliar with other NAG products and services. The
product range, besides the Fortran-based Library includes:
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the NAG C Library |
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the NAG Fortran 90 Library (fl90)
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the NAG SMP Library |
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the NAG Parallel Library |
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the NAGWare range of Fortran compilers and programming support tools |
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DMC, a suite of software components for data mining and analysis |
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IRIS Explorer, an advanced visualization system for building applications |
NAG also provides a range of consulting and component-licensing services to end user organisations and other companies that,
like NAG, are leading players in their respective fields within the Information Technology industry. The world's leading computer
hardware manufacturers work closely with NAG to ensure that NAG software is optimized for their customers. In addition, they
value the quality of the NAG routines in terms of their accuracy, robustness and reliability when testing their compilers.
Indeed a number of the hardware manufacturers license NAG code and/or expertise in developing their own core numerical libraries.
Software vendors also value NAG software with a growing number using NAG routines at the core of their own software. They
recognise that the accuracy, reliability and robustness of the NAG software significantly reduces their time-to-market and
maintenance costs. These important savings apply equally to in-house projects.
Routines tailored for performance and/or functionality are available through the NAG Consulting Service. Using NAG's large
code base, consultants build cost effective solutions on a quality foundation. In addition, NAG's adherence to industry standards
and cross-platform development skills can be used to revitalise existing code. As Alan Scowcroft, Managing Director, Equities
Quantitative Research, UBS Investment Research said:
- ‘My team uses NAG mathematical routines wherever possible – NAG are the experts here – we stick to what we are good at!’.
Consulting teams are based in Oxford, Chicago and Tokyo. For further details of any of the above products and services, please
go to the NAG
web site.
4 Contacting NAG
(a) Contact with NAG
Queries concerning this library should be directed initially to your local Advisory Service. If you have difficulty in making
contact locally, you can contact NAG directly.
(b) NAG Response Centres
The NAG Response Centres are available for general enquiries from all users and also for technical queries from users with
support.
The Response Centres are open during office hours, but contact is possible by fax, email and telephone (answering machine)
at all times. Please see the
Users' Note or the NAG web sites for contact details.
When contacting one of the NAG Response Centres it helps to deal with you query quickly if you can quote your NAG user reference
and NAG product code.
(c) NAG Web Site
The NAG
web site is an information service providing items of interest to users and prospective users of NAG products and services. The information
is regularly updated and reviewed, and includes implementation availability, descriptions of products, down-loadable software
and technical reports. The NAG
web site can be accessed via:
© The Numerical Algorithms Group Ltd, Oxford, UK. 2005